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A portable AFO solution for pneumatic actuator with cable tendon mechanism to assist ankle dorsiflexion

The limited portability of pneumatic pumps presents a challenge for ankle-foot orthosis actuated by pneumatic actuators. The high-pressure requirements and time delay responses of pneumatic actuators necessitate a powerful and large pump, which renders the entire device heavy and inconvenient to car...

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Autores principales: Wang, Junming, Shu, Jing, Su, Yujie, Hu, Chengpeng, Yeung, Ling-Fung, Li, Zheng, Tong, Raymond Kai-Yu
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10621736/
https://www.ncbi.nlm.nih.gov/pubmed/37929198
http://dx.doi.org/10.3389/fbioe.2023.1227327
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author Wang, Junming
Shu, Jing
Su, Yujie
Hu, Chengpeng
Yeung, Ling-Fung
Li, Zheng
Tong, Raymond Kai-Yu
author_facet Wang, Junming
Shu, Jing
Su, Yujie
Hu, Chengpeng
Yeung, Ling-Fung
Li, Zheng
Tong, Raymond Kai-Yu
author_sort Wang, Junming
collection PubMed
description The limited portability of pneumatic pumps presents a challenge for ankle-foot orthosis actuated by pneumatic actuators. The high-pressure requirements and time delay responses of pneumatic actuators necessitate a powerful and large pump, which renders the entire device heavy and inconvenient to carry. In this paper, we propose and validate a concept that enhances portability by employing a slack cable tendon mechanism. By managing slack tension properly, the time delay response problem of pneumatic actuators is eliminated through early triggering, and the system can be effectively controlled to generate the desired force for dorsiflexion assistance. The current portable integration of the system weighs approximately 1.6 kg, with distribution of 0.5 kg actuation part on the shank and 1.1 kg power system on the waist, excluding the battery. A mathematical model is developed to determine the proper triggering time and volumetric flow rate requirements for pump selection. To evaluate the performance of this actuation system and mathematical model, the artificial muscle’s response time and real volumetric flow rate were preliminarily tested with different portable pumps on a healthy participant during treadmill walking at various speeds ranging from 0.5 m/s to 1.75 m/s. Two small pumps, specifically VN-C1 (5.36 L/min, 300 g) and VN-C4 (9.71L/min, 550 g), meet our design criteria, and then tested on three healthy subjects walking at normal speeds of 1 m/s and 1.5 m/s. The kinematic and electromyographic results demonstrate that the device can facilitate ankle dorsiflexion with a portable pump (300–500 g), generating sufficient force to lift up the foot segment, and reducing muscle activity responsible for ankle dorsiflexion during the swing phase by 8% and 10% at normal speeds of 1 m/s and 1.5 m/s respectively. This portable ankle robot, equipped with a compact pump weighing approximately 1.6 kg, holds significant potential for assisting individuals with lower limb weakness in walking, both within their homes and in clinical settings.
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spelling pubmed-106217362023-11-03 A portable AFO solution for pneumatic actuator with cable tendon mechanism to assist ankle dorsiflexion Wang, Junming Shu, Jing Su, Yujie Hu, Chengpeng Yeung, Ling-Fung Li, Zheng Tong, Raymond Kai-Yu Front Bioeng Biotechnol Bioengineering and Biotechnology The limited portability of pneumatic pumps presents a challenge for ankle-foot orthosis actuated by pneumatic actuators. The high-pressure requirements and time delay responses of pneumatic actuators necessitate a powerful and large pump, which renders the entire device heavy and inconvenient to carry. In this paper, we propose and validate a concept that enhances portability by employing a slack cable tendon mechanism. By managing slack tension properly, the time delay response problem of pneumatic actuators is eliminated through early triggering, and the system can be effectively controlled to generate the desired force for dorsiflexion assistance. The current portable integration of the system weighs approximately 1.6 kg, with distribution of 0.5 kg actuation part on the shank and 1.1 kg power system on the waist, excluding the battery. A mathematical model is developed to determine the proper triggering time and volumetric flow rate requirements for pump selection. To evaluate the performance of this actuation system and mathematical model, the artificial muscle’s response time and real volumetric flow rate were preliminarily tested with different portable pumps on a healthy participant during treadmill walking at various speeds ranging from 0.5 m/s to 1.75 m/s. Two small pumps, specifically VN-C1 (5.36 L/min, 300 g) and VN-C4 (9.71L/min, 550 g), meet our design criteria, and then tested on three healthy subjects walking at normal speeds of 1 m/s and 1.5 m/s. The kinematic and electromyographic results demonstrate that the device can facilitate ankle dorsiflexion with a portable pump (300–500 g), generating sufficient force to lift up the foot segment, and reducing muscle activity responsible for ankle dorsiflexion during the swing phase by 8% and 10% at normal speeds of 1 m/s and 1.5 m/s respectively. This portable ankle robot, equipped with a compact pump weighing approximately 1.6 kg, holds significant potential for assisting individuals with lower limb weakness in walking, both within their homes and in clinical settings. Frontiers Media S.A. 2023-10-19 /pmc/articles/PMC10621736/ /pubmed/37929198 http://dx.doi.org/10.3389/fbioe.2023.1227327 Text en Copyright © 2023 Wang, Shu, Su, Hu, Yeung, Li and Tong. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Bioengineering and Biotechnology
Wang, Junming
Shu, Jing
Su, Yujie
Hu, Chengpeng
Yeung, Ling-Fung
Li, Zheng
Tong, Raymond Kai-Yu
A portable AFO solution for pneumatic actuator with cable tendon mechanism to assist ankle dorsiflexion
title A portable AFO solution for pneumatic actuator with cable tendon mechanism to assist ankle dorsiflexion
title_full A portable AFO solution for pneumatic actuator with cable tendon mechanism to assist ankle dorsiflexion
title_fullStr A portable AFO solution for pneumatic actuator with cable tendon mechanism to assist ankle dorsiflexion
title_full_unstemmed A portable AFO solution for pneumatic actuator with cable tendon mechanism to assist ankle dorsiflexion
title_short A portable AFO solution for pneumatic actuator with cable tendon mechanism to assist ankle dorsiflexion
title_sort portable afo solution for pneumatic actuator with cable tendon mechanism to assist ankle dorsiflexion
topic Bioengineering and Biotechnology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10621736/
https://www.ncbi.nlm.nih.gov/pubmed/37929198
http://dx.doi.org/10.3389/fbioe.2023.1227327
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